Each cohort of subjects will be dosed sequentially approximately three weeks apart for the single dose period, and return to the study unit approximately two weeks after their single dose administration to receive 7 consecutive days of dosing for the multiple-dose period. Each cohort of subjects in the multiple-dose period will be dosed sequentially, approximately, two weeks apart (from multiple dose period Day 7 of preceding cohort to multiple dose period Day 1 dose of the subsequent cohort), allowing for a comprehensive safety assessment prior to initiation of an escalated dose in a subsequent cohort.